Jesus was about to be placed on the cross to die. So, He and his twelve apostles decided to have a last supper with bread and water. The symbolic water represented His blood that He gave for us on the cross. The symbolic water represents the blood that He shed for us on the cross. This is called the Last Supper.
This should not become a rite or ritual. We need to do this in remembrance of Him. We should not drink excessive water, grape juice, or wine and we should not eat excessive bread and crackers. If we are hungry, we have food at home or someone can give you food after the Lost Supper. Discipline should be practiced during this time. This should be a time of remembering Jesus.